An Erie County Sheriff's helicopter searches at the scene of a shooting Wednesday at Erie Count Medical Center in Buffalo, N.Y. A police official confirmed a woman was killed Wednesday morning on the grounds of the Erie County Medical Center, which he describes as being in "complete lockdown" as SWAT teams and other officers cordon off the 65-acre campus. (ASSOCIATED PRESS / David Duprey)

BUFFALO, N.Y. (AP) — Police were searching for a trauma surgeon Wednesday as a “person of interest” in a fatal shooting at a Buffalo hospital, and warned the public that the former Army Special Forces weapons expert may be armed and dangerous.

The early morning shooting of a 33-year-old woman locked down the Erie County Medical Center complex for more than four hours. The woman was shot four times while in the stairwell of a hospital building.

Authorities identified the victim as Jacqueline Wisniewski, a receptionist at the hospital and the mother of a young son. Media reports said she was the ex-girlfriend of the surgeon.

Police later blocked a road leading to Dr. Timothy Jorden’s home in an isolated area of private Lake View residences near the Lake Erie shore. SWAT team members in camouflage arrived in unmarked SUVs. A helicopter flew over the house before leaving.

Jorden, 49, also a former Army Special Forces medic, became licensed to practice medicine in New York in 2002 and held privileges to treat patients at the medical center and other major hospitals in the area. He apparently has no criminal background and no legal actions have been filed against his license.

By late Wednesday evening, police told local media the Jorden house was empty and they began leaving the property.

Throughout the day, local, state and federal law enforcement declined to answer specific questions about Jorden, his relationship with the victim or where they thought he might be. They also did not confirm Wisniewski was the victim. Calls to several family members of Wisniewski were either to outdated phone numbers or were not immediately returned.

Wisniewski used to live with Jorden but left him because she believed he was having affairs with other women, Shipley said. When they broke up, he wouldn’t let go, Shipley said.

She said Wisniewski told her the doctor had put a GPS tracking device in her car and once held her captive in her home for a day and a half, wielding a knife.

“She told me if anything happened to her, that it was him,” Shipley told the station.

Calls to two listings in Washington state for Jorden’s ex-wife, Frances, were nt returned.

Hospital chief executive officer Jody Lomeo did not answer specific questions about Jorden or Wisniewski. He said only that Jorden “was a fine doctor.”

According to a 1996 profile in The Buffalo News, Jorden is a native of Buffalo.

Police Commissioner Daniel Derenda said the shooting wasn’t a random act. After the shooting inside a building adjacent to the hospital’s main building, police searched inside for the gunman for more than four hours. A SWAT team was called in.

The search ended by the afternoon, but police were still collecting evidence at the hospital.

The shooting caused a lockdown of the medical center’s 65-acre campus that was lifted at around noon for all buildings except the one being searched by police. Incoming patients were diverted to another hospital during the lockdown.

Police haven’t released any information on the victim, other than her age. They said she was shot shortly after 8 a.m. inside the building that houses outpatient services and offices.

A police helicopter circled over the medical center’s campus, which includes a 550-bed hospital. Officials said as many as 400 patients and about half of the hospital’s 2,000 employees were on the grounds at the time of the shooting. The hospital said grief counseling was made available to employees.

“It’s a very sad day for ECMC and our community,” Lomeo said. “Our thoughts and prayers are with the victim.”

Nikita Patel, a 25-year-old University at Buffalo medical student from Los Angeles, said she arrived at the hospital at about 9 a.m. for a class and was kept from entering. She texted fellow students inside the hospital to find out what was happening.

“They said they’re locked in and can’t get out of the hospital and I can’t go in,” Patel said.

Jorden has a medical degree from the University at Buffalo and trained at the Madigan Army Medical Center in Tacoma, Wash. He received his certification from the American Board of Surgery in 2004.

The News reported that Jorden joined the National Guard in high school, went into the Army after graduation and served with the Army’s Special Forces, first as a weapons expert, then as a medic. In those roles, he served in the Caribbean, Japan and Korea.

Jorden is certified in advanced-trauma life support and has received numerous awards recognizing his relationships with patients, his teaching skills and his involvement in the community, the newspaper said.